1) Field of the Invention
This invention relates to devices useful in cutting materials which produce high volumes of fine dust and debris, particularly industrial materials, and more particularly concrete, and in collecting dust resulting from that cutting by vacuuming. More particularly, it relates to a circular saw which improves the pick-up of concrete dust by an intake tube of a vacuum cleaner collecting dust produced in the cutting of dust-producing materials, particularly uncured concrete. The invention also relates to an improved vacuum cleaner which is of the type using water as a filtering system.
2) Description of the Related Art
Regarding the technology of concrete cutting there are two basic methods employed. The first, and increasingly most common, is dry cutting. This is done while the concrete slab is still green, which is the state of incomplete curing. The other is wet sawing. This is done when the slab is cut after it is completely cured. This technology requires the continuous flow of water to the cutting blade thereby creating a slurry of water and concrete dust.
The previous method for picking up the dry material is with a dustpan and broom. This is so because high volumes of fine dust has a tendency to clog conventional filter. For large slab cuts this is a very inefficient method of collection. For wet cuts, the slurry is not removed until dried. By then most of the residue is spread to a point that is hard to get up. The prior art is aware of a circular saw having a guard blade for cutting concrete, which saw is connected to a vacuum cleaner. Such a device is taught by U.S. Pat. No. 5,084,972 issued to Waugh Feb. 4, 1992.
Vacuum cleaners in which air carrying debris enters through a flexible intake hose, travels between an outer wall and an inner wall, passes through a layer of water which collects a portion of the debris, passes through at least one filter, and exits the vacuum cleaner are known in the art. Examples of publications teaching such vacuum cleaners are U.S. Pat. No. 5,205,014 issued Apr. 27, 1993 to Yoo and U.S. Pat. No. 5,925,171 issued Jul. 20, 1999 to Pietrobon. While it is assumed that the devices disclosed by these patents work satisfactorily for the intended purpose, it is desirable to make improvements such as decreasing the complexity of the apparatus and the amount of material required to manufacture similar devices.